Wednesday 12 June 2013 12.12 EDT
First published on Wednesday 12 June 2013 12.12 EDT

As the Obama administration insists that Congress was fully informed about the National Security Agency's widespread surveillance on Americans' phone records, its intelligence chief is becoming a complication.

James Clapper, the director of national intelligence, has now admitted he gave the "least untruthful" answer to a direct question in March about the extent of surveillance on US citizens. The admission sets up a critical test of Clapper's relationship with the congressional committees that oversee him – committees the Obama administration is relying on for its defense of the surveillance efforts.

The Obama team is expressing support for Clapper as criticism of him mounts. "The president has full faith in director Clapper and his leadership of the intelligence community," National Security Council spokeswoman Caitlin Hayden told the Guardian on Wednesday.

At least one member of Congress is calling for Clapper's head. On his Facebook page, Justin Amash, a Michigan Republican, wrote that Clapper "lied under oath" to Congress.

"It now appears clear that the director of national intelligence, James Clapper, lied under oath to Congress and the American people," Amash posted on Wednesday morning. "Members of Congress can't make informed decisions on intelligence issues when the head of the intelligence community wilfully makes false statements. Perjury is a serious crime. Mr Clapper should resign immediately."

At a hearing of the Senate intelligence committee on 12 March, Oregon Democrat Ron Wyden grew frustrated that he could not get a "direct answer" from Clapper about a question Wyden said he had been posing to the intelligence agencies in a series of letters for a year: when do US spies need a warrant to surveil Americans' communications?

"What I wanted to see is if you could give me a yes or no answer to the question: does the NSA collect any type of data at all on millions or hundreds of millions of Americans?" Wyden asked Clapper.

"No, sir," Clapper said. "Not wittingly. There are cases where they could inadvertently, perhaps, collect, but not wittingly."

Clapper's claim to Congress was undermined by an April order of the secretive Fisa court instructing Verizon to turn over phone records on millions of Americans to the National Security Agency. Published by the Guardian, the order explicitly authorized the NSA to collect so-called metadata "between the United States and abroad; or wholly within the United States, including local telephone calls." An NSA data-mining program, called Boundless Informant and also revealed by the Guardian, further allows the NSA to sort its collected communications by country of origin.

Clapper defended himself in a surprising way. He told NBC's Andrea Mitchell this week that the question was unfair, akin to asking him when he was going to stop beating his wife. "So I responded in what I thought was the most truthful, or least untruthful manner by saying no," Clapper said.

Wyden, the senator who posed the question to Clapper, all but called the director of national intelligence a liar.

"One of the most important responsibilities a senator has is oversight of the intelligence community. This job cannot be done responsibly if senators aren't getting straight answers to direct questions," Wyden said Tuesday.

On Sunday, Clapper received the support of the chairwoman of the Senate intelligence committee, Dianne Feinstein, who told ABC: "There is no more direct or honest person than Jim Clapper. You can misunderstand the question."

But Wyden said he informed Clapper of the question the day before the March hearing, and gave him a chance to correct the record.

"So that he would be prepared to answer, I sent the question to Clapper’s office a day in advance," Wyden said on Tuesday. "After the hearing was over my staff and I gave his office a chance to amend his answer. Now public hearings are needed to address the recent disclosures and the American people have the right to expect straight answers from the intelligence leadership to the questions asked by their representatives."

Currently, the White House is standing behind Clapper. Obama "certainly believes that Clapper has been straight and direct in the answers that he's given, and has actively engaged in an effort to provide more information about the programs that have been revealed through the leak of classified information," press secretary Jay Carney said on Tuesday, calling Clapper "aggressive in providing as much information as possible to the American people".

Clapper's spokesman, Shawn Turner, did not respond to a request for comment on Clapper's continued service as director of national intelligence.